An overview of structural pattern matching for Python

Algol 68, and Oberon-7 (among other versions) put keywords in a totally separate namespace and reserve the whole space. Everything ALLCAPS in oberon is a keyword, and you must not use such things as identifiers. Similarly algol 68 required surrounding keywords in back-ticks or something.

The middle ground is allowing some kind of stropping to turn what would be a keyword into an identifier, that way you can “update” in an automated fashion

if you have a module system the parser can just parse according to what the module expects.